Accurate progress displayed with UIProgressView for ASIHTTPRequest in an ASINetworkQueue

Question

Summary: I want to track the progress of file downloads with progress bars inside cells of a tableview. I'm using ASIHTTPRequest in an ASINetworkQueue to handle the downloads.
It works, but the progress bars stay at 0%, and jump directly at 100% at the end of each download.

---

Details: I set up my ASIHTTPRequest requests and ASINetworkQueue this way:

[Only an extract of my code]

- (void) startDownloadOfFiles:(NSArray *) filesArray {

    for (FileToDownload *aFile in filesArray) {

        ASIHTTPRequest *downloadAFileRequest = [ASIHTTPRequest requestWithURL:aFile.url];

        UIProgressView *theProgressView = [[UIProgressView alloc] initWithFrame:CGRectMake(20.0f, 34.0f, 280.0f, 9.0f)];
        [downloadAFileRequest setDownloadProgressDelegate:theProgressView];

        [downloadAFileRequest setUserInfo:
            [NSDictionary dictionaryWithObjectsAndKeys:aFile.fileName, @"fileName",
                                                        theProgressView, @"progressView", nil]];
        [theProgressView release];

        [downloadAFileRequest setDelegate:self];
        [downloadAFileRequest setDidFinishSelector:@selector(requestForDownloadOfFileFinished:)];
        [downloadAFileRequest setDidFailSelector:@selector(requestForDownloadOfFileFailed:)];
        [downloadAFileRequest setShowAccurateProgress:YES];

        if (! [self filesToDownloadQueue]) {
            // Setting up the queue if needed
            [self setFilesToDownloadQueue:[[[ASINetworkQueue alloc] init] autorelease]];

            [self filesToDownloadQueue].delegate = self;
            [[self filesToDownloadQueue] setMaxConcurrentOperationCount:2];
            [[self filesToDownloadQueue] setShouldCancelAllRequestsOnFailure:NO]; 
            [[self filesToDownloadQueue] setShowAccurateProgress:YES]; 

        }

        [[self filesToDownloadQueue] addOperation:downloadAFileRequest];
    }        

    [[self filesToDownloadQueue] go];
}

Then, in a UITableViewController, I create cells, and add the name of the file and the UIProgressView using the objects stored in the userInfo dictionary of the request.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"fileDownloadCell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {
        [[NSBundle mainBundle] loadNibNamed:@"FileDownloadTableViewCell" owner:self options:nil];
        cell = downloadFileCell;
        self.downloadFileCell = nil;
    }

    NSDictionary *userInfo = [self.fileBeingDownloadedUserInfos objectAtIndex:indexPath.row];

    [(UILabel *)[cell viewWithTag:11] setText:[NSString stringWithFormat:@"%d: %@", indexPath.row, [userInfo valueForKey:@"fileName"]]];

    // Here, I'm removing the previous progress view, and adding it to the cell
    [[cell viewWithTag:12] removeFromSuperview];
    UIProgressView *theProgressView = [userInfo valueForKey:@"progressView"];
    if (theProgressView) {
        theProgressView.tag = 12;
        [cell.contentView addSubview:theProgressView];
    } 


    return cell;
}

The progress bar are all added, with the progress set to 0%. Then, at end of download, they instantly jump to 100%.

Some of the download are very big (more than 40Mb).

I do not do anything tricky with threads.

Reading the forums of the ASIHTTPRequest, it seems I'm not alone, but I couldn't find a solution. Am I missing something obvious? Is this a bug in ASI* ?

Answer 1

ASIHTTPRequest can only report progress if the server is sending Content-Length: headers, as otherwise it doesn't know how big the response will be. (ASINetworkQueue also sends HEAD requests at the start to try to figure out document sizes.)

Try collecting all the network traffic with charlesproxy or wireshark, see if these headers are present and/or what is happening with the HEAD requests.